More than 50 million people across the Southeast face the threat of severe storms on Monday as widespread power outages have left nearly half a million across the South in the dark, including some sweltering under record-breaking temperatures.
A level 2 of 5 slight risk of severe weather is in place across parts of the Gulf Coast and Southeast, including the cities of New Orleans and Baton Rouge in Louisiana, Jacksonville, Florida; Mobile, Alabama; and Savannah, Georgia. The main threats are damaging wind gusts, large hail and isolated tornadoes.
A level 1 of 5 marginal risk stretches from central Texas to southern Florida and north to western North Carolina, leaving cities like Atlanta, Charlotte, North Carolina; Austin, Texas; and Tampa, Orlando and Miami in Florida under the threat of large hail and damaging wind gusts.
The same system spawned a reported tornado in Mississippi late Sunday, leaving multiple injuries and structural damage around Bay Springs and Louin, according to preliminary reports from the National Weather Service.
Meanwhile, around 35 million people are under heat alerts from a blistering heat wave that has settled across much of Texas, Louisiana and southern New Mexico and Mississippi, according to the National Weather Service.
Many are facing the heat without air conditioning as nearly 500,000 customers were without power in the South as of Monday morning -- including more than 200,000 in Oklahoma and more than 90,000 in Texas and another 85,000 in Louisiana, according to PowerOutage.us.
The National Weather Service is advising residents to stay inside during the hottest part of the day, drink plenty of water and not leave children or pets in vehicles.
"In case we haven't said it enough," the National Weather Service Midland, Texas, tweeted, it's going to be "HOT. Try to spend as little time as possible outdoors, but if you must be outside, take frequent breaks in the AC, drink plenty of water & spend as much time as possible in the shade."
As the heat wave continues, over 40 daily records could be tied or broken across Texas this week. The worst of the heat is expected from Monday through Wednesday.
The combination of temperature and humidity -- or the heat index -- could climb to 113 to 122 degrees in cities like Houston, San Antonio, Brownsville and Dallas.
Several daily heat records were already broken on Sunday. Del Rio, Texas, recorded a temperature of 111 degrees Sunday, breaking a previous daily record of 106 degrees set in 2011. Austin Camp Mabry, Texas, tied its record of 106 degrees set a dozen years ago and McAllen, Texas, reported a record-breaking 105 degrees.
"Temperatures in the 100s will not only rival daily high temperature marks for the nation but may tie or break existing records," the National Weather Service said. "There will be little relief overnight with lows in the upper 70s and 80s."
Cities across the south -- some still cleaning up from last week's storms -- are preparing for hot weather by opening cooling centers.
The City of Houston is opening cooling centers from 3 p.m. to 7 p.m. CT on Sunday and Monday as the city braces for high temperatures. Caddo Parish in Louisiana has opened additional cooling centers as the parish still grapples with power outages and storm cleanup.
New Orleans' emergency preparedness campaign is working with the New Orleans Fire Department to set up hydration stations to provide water and sunscreen Sunday and Monday.
Meanwhile, there were more than 70 storm reports across the Southeast on Sunday, including six tornado reports, mostly in central Mississippi, according to the Storm Prediction Center.
Hail 2 inches wide or larger was also reported Sunday in Hunt, Texas, and Kerrville, Texas.
On Monday, the threat of excessive rainfall moves eastward to the southeastern parts of the country, bringing the threat of thunderstorms and flooding over parts of the Southeast, southern Mid-Atlantic, and Southern Appalachians.